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本文对于复杂的岩性反演问题提出了一种用地震速度(c_p,c_s),和密度(ρ)的空间分布作为输入的新体系。在每个地下网格点上,反演结果包括最有可能的岩性型(天然气、砂岩、页岩等等)和与之相关的岩性参数(骨架强度、孔隙度等)。反演方法基于参数估计理论,这个理论允许输入中的一些不精确性成分并可结合地质知识。所提出的反演方法的一个重要优点在于对每种实际情况都能预先确定 c_p,c_s 和ρ的必要精度,以便区分一具体的岩性型或用预先规定的精度估计具体的岩性参数。例如,反演结果表明,只有要求有不切实际精确度的输入才能估计含水饱和度。另一方面,对孔隙度的估计一般用有现实精度的纵波速度就足够了。
In this paper, we propose a new system that uses the spatial distribution of seismic velocity (c_p, c_s) and density (ρ) as input for complex lithological inversion. At each of the subsurface grid points, the inversion results include the most likely lithologies (gas, sandstone, shale, etc.) and associated lithological parameters (skeletal strength, porosity, etc.). The inversion method is based on the parameter estimation theory, which allows for some inaccuracies in the input and incorporates geological knowledge. An important advantage of the proposed inversion method is that the necessary accuracy of c_p, c_s, and p can be predetermined for each actual situation in order to distinguish a particular lithology or to estimate a particular lithology parameter with a predetermined accuracy. For example, inversion results show that water saturation can only be estimated by requiring input that is impractical. On the other hand, it is sufficient to estimate the porosity with a pragmatic wave velocity of a realistic accuracy.